From what I've seen in residential Tokyo, houses are usually one offs built when the owner buys the land. And look, at least superficially, to be similar construction methods to American construction rather than European: i.e. wood framing as opposed to masonry/concrete.
Maybe some of it is prefab, but given the narrowness of roads, I wonder.
You are correct. The SFHs in Tokyo are usually built roughly similar to stick-built (slightly post-and-beam, but walls are load-bearing). Wood can be precut to length, but they are constructed on-site.
Maybe some of it is prefab, but given the narrowness of roads, I wonder.